Friday, April 24, 2015

Brake Master Cylinder Mock-Up

It’s
been far too long between updates, I admit, but a lot of custom Harley work has
kept me very busy for the past few months along with some pretty major occurrences
at home that have demanded just about every spare moment I had (more on that is
the coming weeks).However, much to the
chagrin of most of my neighbors and even a few family members, I am NOT dead in
spite of the rumors and wishes to the contrary!

This
update will be a quick one and somewhat out of sync with the most recent work
on the Boss.I find myself having to
step back from a certain line of thinking for a while to regain perspective and
let the matter “breathe” now and again, and one way I like to do that is to
pick up a project I have let lay and drive it through the goal post if at all
possible.One of these projects has been
to have my original brake booster rebuilt and the other is to configure a
modern aluminum master cylinder as a replacement to the old iron original that,
in my opinion, has too small a fluid reservoir capacity for rear disc brakes.

The
booster rebuild was ultimately a disappointment.No because it wasn’t successful, but because the
condition of my original booster was not up to my standards.When it was all said and done, the two case
halves were pitted from rust when cleaned to bare metal and plated in zinc
dichromate and because the rebuilder was a bit less than tidy in the reassembly
process, leaving many tool marks and gouges along the seam.I guess I had higher hopes given the
rebuilder was perhaps the most highly recommended outfit around but I can’t
complain too much as the price was hardly arguable.The bottom line is it works and will function
as a good spare, but I will be replacing it with a new unit from NPD very soon.

The
master cylinder solution was quite a while in the making as I ended up using a
combination of parts from three different vehicles to get the entire
booster/master cylinder setup I was looking for.The key features I was after was a nice, 1”
bore, modern aluminum master cylinder with the fittings on the outboard side
just like the original.Also, I wanted a
clean, see-thru fluid reservoir and the whole works needed to work within the
stock packaging space.As it turns out,
I might have actually created something that could have some potential for
aftermarket sales if I put my mind to it (but that is another issue
altogether).In the meantime, I will
continue to refine the setup with a Wilwood distribution block with built-in
bias valve and a mounting bracket designed to mount the valve and the reservoir
for the hydraulic clutch as well.But
that being comparatively easy work, I might let that lay a bit while I return
to working on the doors and mirrors!

Lots of research went into getting this master cylinder combo to work on the original '70 Mustang Bendix booster. This booster is my rebuilt original and will only be used as a mock-up donor and spare. It's just not looking good enough for the project, but you get the idea.

Another shot from the top shows how much cleaner and slimmer the modern master cylinder is over the old iron unit.

Almost all of the popular master cylinder conversions that use the plastic fluid reservoirs have the ports on the inboard side. This complicates many aspects of working on the engine and looks too cluttered for my taste. This setup puts the ports in the same (outboard) location as the original master cylinder and offers a lot more working room on both sides.

Clearance to the shock tower is exactly the same as the stock iron master cylinder!

Thanks Grant! Once I get some time to prove-out all the bits involved in putting this together, I will follow up with more detail on how to reproduce it. It's a little expensive in that I combine parts from three different car models to get the whole thing together, so the initial investment is quite a bit more than just throwing on an original replacement M/C. But what fun would that be?!

Well Sven, our lives must be parallel! Work. Home. Life. I guess we all have at one time or another "restorus interruptus"!!! But progress is progress. There was a website called Ultrastang.com, but it's apparently gone. He was a good source of using later model Mustang brake boosters and master cylinder on vintage Mustangs. I'm going to use a setup out of a 92 GT for mine. You're right. The newer style is more compact and tidy looking. Mustang Steve's might be another option for Grant. I guess there's still a little old school hot rodder in me...use good parts off other cars. Keep on keeping on my friend!!!

Howdy Dennis and thanks for the comment! Life has definitely gotten complex in recent months!

I have looked at all of the popular modern booster/master cylinder conversions out there and I didn't care for any of them for my particular project. I like the Bendix booster size that came on the car and the look of it as well. With a modern M/C on it, it looks quite tidy and far from pout of place on the car. Plus I can get service M/C's that will work with 4-wheel discs at almost any parts store while I wait. That is just a bit more peace of mind on a car I plan to drive a lot! Cheers sir!

Sven, I too am interested in the MC solution you are doing. I've recently bought my dream car (a '69 Convertible) and am converting the rear over from stock 8" drum axle to an 8.8" with disc this coming winter. My MC will need to be swapped so I'm hoping for the same as you have found: Clean, plastic reservoir, fittings on proper size. Can you provide any more details?

For those of you looking at this setup, I am bench bleeding the master and wanted to give a data point FYI. The initial 1/4" of stroke or so only pushes fluid out the rear brake (forward) port, the next 3/4" pushes both ports, then remaining 1/2" of stroke pushes fluid out the front brake (rearward) port. Master cylinder is A-1 CARDONE 102532 (10-2532) from a 92 Ranger [has 'BENDIX' cast in it], Resovoir is a A-1 CARDONE 1R2949 (1R-2949) from a 00 V6 Mustang. Fit is perfect, bought metric lines and reflared with SAE fittings to match the Mustang parts. My system is 69 drum car converted to stock 69 front disc, stock 95 Mustang rear disc [full 8.8. swap], factory (I presume but cannot confirm as the front was converter before me) booster, factory 69 distribution block (from drum/drum so no proportioning) and a Wilwood adjustable proportioning valve on the rear line. Hope to have the car on the road in the next 2 weeks and will let you all know how it works! Still need to decide if I am going to use the new res. low fluid sensor and wire it in parallel with the factory brake switch on the distribution block.. Seems like it might be smart as it will give low fluid warning as opposed to a line failure from the factory switch. Thoughts anyone?

Test drive is satisfactory, but there is enough of the car undone (all new pads, half the dash out, and swapped tranny and rear) I can't give a final approval yet.. Want to really shake it down and see but encouraging! Note for those of you doing the swap: The brake switch on the 2000 res. takes a pigtail that is the same as a Ford 6G series alternator which is easier to find. The correct part number is a WPT118 (which is stupid expensive) but apparently that crosses to a 1U2J-14B475-TA and 1U2Z-14S411-TA also. Grabbed one new of ebay for $12 shipped and fits fine. The sensor is just a magnetic float switch, with a normally open pin (forwardmost) and the other two pins are connected internally (middle and rearward). Closes them all on low fluid situation. I did mid & rear to ground, front to the idiot light. I also wired in parallel with 2 pin sensor on the stock distribution block so low fluid (res.) or loss of pressure (dist. block) will turn the light on.